Can laughter really keep the doctor away?
The level of humour shown at Laughter Yoga is not particularly high. An unusual movement or a funny noise, and the 10 members of this Frankfurt laughter club called "Glueck ist jetzt" (Happiness is Now) giggle, snort or erupt into guffaws.
Humour, after all, is not the point for the members, rather the laughing itself. "Fake it until you make it," is the motto, according to Laurenz Menzinger - in other words pretend as long as needed for it to become real.
Menzinger is a human resources consultant, but one evening a week he leads this Laughter Yoga group held in small and brightly decorated business premises in the inner city of the German financial capital.
A year ago he qualified as a certified laughter yoga teacher according to a method developed by an Indian doctor. Menzinger underwent training in Switzerland, learning breathing techniques, stretching and laughing exercises, such as the laugh shower and the sorry-excuse-me laugh.
"Laughter stimulates both body and mind," he says. "If you laugh properly, you forget your everyday cares." The club's homepage points out that laughter yoga provides an "effective cardio workout."
Laughter's beneficial effects on health are well documented. "Laughing stimulates the entire circulation system," says Swiss neurologist Juerg Kesselring of the Valens Clinic.
"The resultant quicker breathing improves blood flow, and that is what makes laughing healthy," he says. Laughter also boosts the immune system. "A genuine and hearty laugh activates more T-cells than usual, and this boosts the immune capacity."
However, Kesselring cautions against overstating the beneficial effects. "Laughter is certainly able to promote the body's capacity to heal itself, but it can probably not heal diseases all on its own," he says.
Rainer Stollmann, a professor at the University of Bremen who has studied laughter, remains sceptical of the 150 laughter clubs spread across Germany.
"First we had Primal Scream Therapy, then cuddle clubs, and now there are laughter yoga societies," he says. "But the point about laughter that is the most important for me - humour, or probing our own weaknesses - that's missing with Laughter Yoga."
These reservations count for little at the Frankfurt laughter club. World Laughter Day, marked each year on the first Sunday in May, brought the members out onto the streets to stimulate members of the public to join in the laughter on the main square in the old city, the Roemerberg.
"Of course, some people just shake their heads in incomprehension, and not everyone is able to join in this childish game," Menzinger acknowledges. But he insists that the thousands of laughter clubs all over the world make clear that many people find that laughter enhances their lives.